Piezostrain-enhanced photovoltaic effects in BiFeO3/La0.7Sr0.3MnO3/PMN–PT heterostructures

Abstract BiFeO 3 (BFO) is a unique multiferroic material that shows interesting but rather weak photovoltaic effect. Here, we report the integration of Pt/BFO/La 0.7 Sr 0.3 MnO 3 (LSMO) photovoltaic devices on piezoelectric 0.71Pb(Mg 1/3 Nb 2/3 )O 3 –0.29PbTiO 3 (PMN–PT) single-crystal substrates and realized a piezo-photovoltaic effects in the BFO/LSMO/PMN–PT heterostructures through in situ dynamical strain engineering. Upon the application of an electric field of +10 kV/cm, an in-plane compressive strain was induced in the PMN–PT via the converse piezoelectric effect, which was effectively transferred to the BFO film through the LSMO, leading to a change in the in-plane strain and bandgap of the BFO film by ~0.12% and ~22 meV, respectively. As a result, the power conversion coefficiency (PCE) η was dramatically enhanced by ~218%, corresponding to a gauge factor (Δ η / η )/ δe xx ~1817. The results demonstrate that the dynamic strain engineering of photovoltaic properties using the converse piezoelectric effect is an effective and unique approach for realizing enhanced PCE of ferroelectric thin film-based photovoltaic devices.